The RDA of vitamin A for pregnant women is only 2,600 IU—just 300 IU
more than the RDA for women who are not pregnant. To obtain this figure,
the scientists at the Institute of Medicine (IOM) made the following
calculation: first, they ascertained from previous reports the amount of
vitamin A stored in the livers of fetuses that were spontaneously or
voluntarily aborted between 37 and 40 weeks; second, they doubled this
figure, assuming that half of the fetal vitamin A stores exist in the
liver; and third, they divided this amount over the number of days in
the last trimester, during which they presumed this vitamin A would
accumulate.20
There are several problems with this calculation. Since the fetuses
were aborted, we have no idea what their future health would have been
like—their visual acuity, their hearing, their intelligence, their
facial and dental features, their reproductive health, or their length
of life. And the function of vitamin A, of course, is not to be stored
but to be used. The fetus does not simply hold on to vitamin A to use it
after birth, but rapidly uses and metabolizes it to regulate the
entirety of its growth and development. Granted, the IOM acknowledges
that it has only used this data because better data do not exist—yet it
is important to emphasize just how little the data tell us.
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